Indicator for sewing machines



June 21, 1960 K. wmz 2,941,487

INDICATOR FOR sswmc MACHINES Filed March 19, 1956 3 Sheets-Sheet l 34 INVENTOE l ar/ lV/IVZ my '24: Armelvsy I June 21, 1960 K. wlNz INDICATOR FOR SEWING MACHINES 3 Sheets-Sheet 2 Filed March 19, 1956 Fig. 2a

INVENTOR.

BY kar/ W/IVZ kw M rroe/vs y June 21, 1960 K. wmz

INDICATOR FOR SEWING MACHINES Filed March 19, 1956 3 Sheets-Sheet 3 FIG- 3 INIt'NIOP 7 Karl Wl/VZ *Armmvn United States Patent 2,941,487 INDICATOR FOR SEWING MACHINES Karl Winz, Kaiserslautern, Pfalz, Germany, assignor to G. M. Pfalf A.G., Kaiserslautern, Pfalz, Germany, a corporation of Germany The present invention relates to improvements in sewing machines, more particularly machines of the type comprising separate lower and upper feeds and means for controlling'the operating stroke of one feed relative to the stroke of the other feed.

Among other uses, the provision in machines having a dual feed and control means for varying the differential stroke between the feeds one relative to the other has special advantages in sewing several layers of material which frequently makes it necessary to accommodate an excess width of one layer of material relative to another layer during the sewing operation. Such excess width may be accommodated with machines comprising a dual feed, in particular machines having separate upper and lower feed means, by a variation of the feeding stroke of one of the feeds, such as the upper feed, relative to the stroke of the other feed.

It has already become known in machines of this type to provide suitable control or operating means, whereby the feed stroke may be varied continuously by the operator during the course of a sewing operation.

However, in the previous constructions for varying the feed stroke, the control and adjustment is highly dependent on the personal factor or feel of the operator who at the instant of sewing is not in a position to determine whether the feed adjustment conforms with the existing requirements of the sewing operation. Only after the sewing operation has been completed is it possible to determine or check the adjustment made.

An important object of the present invention is, therefore, the provision of improved indicating means substantially overcoming the aforementioned and related disadvantages by enabling a positive and instant control of the differential stroke in machines having a dual feed, to suit existing desires and sewing requirements.

A more specific object of the invention is the provision of positive and instant indicating means enabling an accurate control of the differential feed adjustment between the strokes of a pair of combined feed devices, in particular between the upper and lower feeds of a conventional sewing machine.

The above and ancillary objects as well as novel as pects of the invention will be better understood from the following detailed description taken in reference to the accompanying drawings, forming part of this specification and wherein:

Fig. 1 is a perspective view of a sewing machine equipped with separate upper and lower feeds and embodying differential feed control and indicating means in accordance with the invention;

Fig. 2 is a partial perspective view of Fig. 1 showing the base member and upright of the machine in relative open position to show the differential feed control mechanism;

Fig. 2a is a fragmentary perspective view more clearly illustrating the control of the upper feed from the lower feed by the mechanism shown by Fig. 2;

Patented June 21, 1960 multiple contacts cooperating with a potentiometer resis-' tor and an electrical indicating instrument;

Fig. 5 shows another embodiment of an indicating system utilizing a pressure sensitive resistor and an electrical indicating instrument; and

Fig. 6 illustrates an embodiment of a mechanical remote indicator constructed in accordance with the principles of the invention.

Like reference characters identify like parts in the different views of the drawings. 1

With the foregoing objects in view, the invention involves generally the provision of visual indicating'means arranged to be readily visible to the operator in the normal viewing direction and controlled either electrically or mechanically and in dependence upon the operation of an adjusting organ effective in varying the differential stroke between the upper and lower feed of a conventional duplex feed sewing machine.

The indication may be efiected in various manners, such as by means of an array of electrical indicator lamps, an electrical indicating instrument, a luminous indicator cooperating with an adjustable mask or shutter and the like. The connection with or remote control of the indicator by the adjustable organ of the machine effective in varying the differential feed adjustment may be effected either electrically through a remote control circuit or mechanically by means of a flexible link such as chain, string or the like coupling element.

Referring to Figs. 1, 2 and 2a of the drawing, there is shown a conventional dual feed sewing machine comprising a head 1, an upper or overhanging arm 2, a standard or upright 3, and a bed or lower arm 4. The standard 3 is supported by a base member 5, being connected thereto by a hinge 6 and secured by means of locking lever 7 and wingnut 8. Mounted in conventional manner within the upper arm 2 of the machine are the main driving shaft 9 and the actuating shaft 10 or link for the upper feed, while the actuating shaft 11 for the lower feed is mounted within the lower arm 4. Furthermore, mounted in known manner upon the main driving shaft 9 is an eccentric element 12 which is connected to a crank 14 secured to the lower feed actuating shaft 11 through a suitable connecting link 13. The latter is provided in a known manner with an adjustable stitch controller 15.

An oscillating arm 16 connected to the shaft 11 by means of clamping sleeve 17 is provided with a slot 18 within which is disposed a sliding block (not shown) secured to a pin 19 journalled in the bifurcated end 20 of a further connecting link 21 coupling the shaft 11 with the upper feed control shaft 10. For this purpose, the opposite end of the link 21 may be pivoted to an oscillating arm 22 secured to the upper feed actuating shaft.

By the action of a coil spring 23 the connecting link 21 is urged against theend of the slot 18 of the oscillating arm 16 adjacent to the shaft 11. For this purpose,

the spring 23 has a hooked end engaging the link 21 and' is secured with its opposite end to the standard 3 by' 3) a the bifurcated end 20 of the link 21 and the shaft 11. The opposite arm 31 of the lever 25 has secured to it the end of chain 32 passing through an opening 3 of the base plate 34 and having its other end connected to a suitable control element, such as a treadle, knee lever or the like.

The upper and lower feeds operated by the rock shafts 1 0 and 11, respectively, may be of any known type and construction. Thus, shaft 11 may operate a conventional lower feed dog, while the shaft may drive an oscillating needle bar to advance the work by the needle in synchronism with the lower feed, in a manner well known. There is shown for this purpose in Fig. 2a of the drawing an oscillating member 100 pivoted at 101 and carrying a reciprocating needle bar 102. The latter is connected to a crank 105 mounted upon the main drive shaft 9 through a joint 103 and link 104 to apply vertical reciprocating movement to the needle bar 192. The upper feed rock shaft 10 controlled by the lower feed shaft 11 through the adjustable coupling mechanism as described herein is connected with the oscillating member 100 through a crank 106, whereby to oscillate the needle held by the bar 102 horizontally, to serve as upper feed cooperating with the lower feed of the duplex feed control.

In operation, in the normal position, that is, with no force acting on the lever arm 31, the sliding block at the lower end 20 of the link 21 is urged against the inner end of the slot 18 by the action of the spring 23. In this position the stroke of the upper feed equals the stroke of the lower feed. If now the lever arm 25 is deflected by a pulling force on the chain 32 or in any other suitable manner, the lever will be rotated to a position, whereby, by the action of its bifurcated arm 30, the lower end 20 and the connecting link 21 is forced in the direction away from the shaft 11 against the action of the spring 23. As a result the effective leverage of the oscillating arm 16 is increased, causing an increase of the stroke of the upper feed relative to the stroke of the lower feed.

According to the embodiment shown of the invention, the pin 26 has a lateral extension 35 carrying an actuating element such as a pin 36 extending therefrom in a radial direction. Furthermore, secured by means of screws 39 to an inner extension 37 of the standard 3 is an angular support or bracket 38 to which are in turn secured canti-lever fashion, and by means of a screw 40, a set 41 of leaf springs 43 separated by insulating spacers 42 and carrying a number of trailing contacts 44 at the free ends thereof.

The indicator in the embodiment shown by Fig. 1 comprises a casing 45 secured to the head 1 of the machine so as to be readily visible to the operator in the normal viewing direction and having mounted therein a row of electrical indicating lamps 46 visible through openings 47 in the front wall of the casing. Fig. 3 shows, by way of example, a circuit diagram of the electrical connections between the trailing contacts 44 actuated by the member 35 in the direction indicated by the arrow a and the indicating lamps 46. According to this embodiment, one terminal of each of the lamps 46 is connected to a terminal of the secondary winding of a stepsdown transformer 49 supplying operating current for the lamps, while the remaining contacts of the lamps 46 are each connected to one of the spring contacts 44. An-additional spring contact 44 adjacent to the actuating member 36 is connected to the remaining terminal of the transformer secondary 49'. The primary winding of the transformer is connected between one supply phase of the three-phase driving motor M and ground or neutral, preferably to a point between the motor and the main control switch 48 as shown in the drawing. As a result, the lamps 46 can be energized only during the operation of the machine, thus preventing acci? dental connections or short circuits. In place of the three-phase motor shown, any other type of driving motor can be provided, while the transformer 49 may be connected to or replaced by any other power source.

In an arrangement of this type, as the difierential stroke between the upper and lower feed is varied by the rotation of the pin or shaft 26, contacts 44 will be progressively short 'circuited, thus causing a consecutive lighting of the lamps 46. The number of lamps lit is thus an indication of the differential adjustment of the dual feed and may be instantly ascertained and/or controlled by the operator during a sewing operation, to suit any instantaneous sewing requirements.

Fig. 4 shows an alternative system of a remote indicator of the differential stroke comprising a series of trailing contacts similar to Fig. 3 actuated or progressively short circuited by a force (member 36) acting in the direction of the arrow b. According to this modification the first contactis connected to the transformer in a manner similar to Fig. 3, while the remaining contacts are connected to successive taps of a potentiometer resistor 51, the end of said resistance being connected to one input terminal of an electrical indicating instrument 52 having a pointer or indicator and cooperating indicating scale. The other terminal of the instrument is connected to the remaining terminal of the secondary winding of the transformer 49. In this case, short circuiting of progressively increasing increments of the resistor 51 will result in a corresponding increase of the deflection of the meter or instrument 52, thus again instantaneously indicating the differential feed stroke controlled or adjusted by the member 25 or an equivalent adjusting organ controlling the differential between the strokes of the upper and lower feed devices.

According to a further modification, Fig. 5, the telemetering system comprises an indicator 52 and transformer secondary 49 connected in series with a pressure sensitive resistor 53, such as a stack of carbon elements having a pressure transmitting member 54 and being subjected to varying stack pressure by the member 25 or equivalent actuating device as indicated by the arrow 0 to control the current through the meter 52 in proportion of the adjusted feed differential to be indicated by the scale of the meter.

Any equivalent device responsive to pressure or displacement known in the art of electrical remote control or indication may be used for the purpose of the invention in place of the carbon resistor 53 shown for illustration, as will readily suggest themselves to those skilled in the art.

While according to the Fig. 3 and Fig. 4 modifications the indication of the differential stroke is incremental or in consecutive steps which may be as close as desired by using an appropriate number of contacts and indicator lamps 46 or taps upon the potentiometer resistor 51, the indication according to Fig. 5 using a compressible carbon resistor is continuous or gradual, thereby enabling a fine control of the differential feed adjustment positively and instantly within the course of a sewing operation.

Finally, Fig. 6 shows a purely mechanical remote control or indicator of the diiferential feed stroke. This may be in the form of a pulling chain or string 59 connected to a lever 25 or member 36, either directly or through an auxiliary linkage arrangement, and being controlled by a balance spring 58. The indication may be effected by the displacement of a shutter or sliding mask 57 in front of a window of a casing 55 having mounted therein a light source, such as an electric bulb, fluorescent lamp and the like, The window may be covered by a ground glass 56 carrying a calibrating scale 6% Whereby displacement of the shutter 57 in accordance with the adjusted feed differential again affords an instantaneous indication of the adjustment by the position of the shutter 57, in a manner readily understood.

There is thus provided by the invention a simple and efiicient means and method to instantaneously indicate the feed stroke differential in a dual feed sewing machine having adjusting means for continuous diiferential feed control. The operator is thus apprised instantly and continuously of the differential feed stroke adjustment, thereby enabling a reliable and accurate control of the adjustment for securing special results, such as the accommodation of varying widths in sewing multiple layers of material, securely and eificiently during the entire course of a sewing operation.

In the foregoing the invention has been described with reference to a specific illustrative device. It will be evident, however, that numerous variations and modifications, as well as the substitution of known elements and parts for those shown for illustration, may be made without departing from the broader spirit and scope of the invention as defined in the appended claims.

The specification and drawings are accordingly to be regarded in an illustrative rather than in a limiting sense.

I claim:

1. In a sewing machine having upper and lower work feed means and coupling mechanism between said feed means including control means, for continuously varying the feed stroke differential between said feed means during the operation of said machine, of visual indicating means viewable in the normal direction of observation of the operator and controlled by said mechanism, to indicate the instantaneous feed stroke differential adjusted by said control means.

2. In a sewing machine having upper and lower work feed means and coupling mechanism between said feed means including control means for continuously varying the feed stroke differential between said feed means during the operation of said machine, of visual indicating means viewable in the normal direction of observation of the operator, and means connecting said mechanism with said indicating means, to indicate the instantaneous feed stroke differential adjusted by said control means.

3. In a sewing machine having upper and lower work feed means and mechanism between said feed means including control means, for continuously varying the feed stroke differential between said feed means during the operation of said machine, of visual indicating means disposed in continuously viewable relation to the operator, and means connecting said mechanism with said indicating means, to indicate the instantaneous feed stroke difierential adjusted by said control means.

4. -In a sewing machine having upper and lower work feed means and coupling mechanism between said feed means including control means, for continuously varying the feed stroke differential between said feed means during the operation of said machine, of visual electrical indicating means viewable in the normal direction of observation of the operator, means to convert the adjusting position of said mechanism into proportionate electric current variations, and circuit means connecting said indicating means with said last-mentioned means, to indicate the instantaneous feed stroke differential adjusted by said control means.

5. In an arrangement as claimed in claim 4, wherein said last means comprises a compressible carbon resistor and source of current connected in series with said indicating means.

6. In an arrangement as claimed in claim 4, wherein said last means is comprised on a set of flexible electrical contacts adapted to be progressively short circuited by said adjusting means, a potentiometer resistor and a source of current in series with said indicating means, said resistor having consecutive tap points connected to said contacts, whereby to incrementally vary the electric current of said source in accordance with the adjusting position of said control means.

7. In a sewing machine having upper and lower work feed means and coupling means between said feed means including control means, for continuously varying the feed stroke differential between said feed means during the operation of said machine, of means to indicate the instantaneous feed stroke diflerential comprising an array of electric indicating lamps mounted upon said machine and viewable in the normal direction of observation of the operator, a current source, and a plurality of flexible contacts arranged to progressively engage one another upon operation of said control means, and circuit connections between said lamps, said source and said contacts, to sequentially energize said lamps in the direction of increasing feed stroke differential.

8. In a sewing machine having a bed, a head, an arm extending therefrom and a standard connecting said arm and bed, upper and lower Work feed means upon said head and bed, respectively, coupling mechanism between said feed means including control means, for continuously varying the feed stroke differential between said feed means during the operation of said machine, of visual indicating means mounted upon said head and viewable in the normal direction of observation of the operator, and means connecting said mechanism with said indicating means, to indicate the instantaneous feed stroke difierential adjusted by said control means.

9. In a sewing machine having a bed, a head, an arm extending therefrom and a standard connecting said arm and bed, upper and lower work feed means upon said head and bed, respectively, coupling mechanism between said feed means including control means, for continuously varying the feed stroke differential between said feed means during the operation of said machine, of an electrical indicator mounted upon said head and visible in the normal viewing direction of the operator, and circuit means including said indicator, a source of electric current and means to convert the adjusting position of said mechanism into proportionate current variations, to indicate the instantaneous feed stroke differential adjusted by said control means.

10. In a sewing machine as claimed in claim 9, wherein said indicator comprises a plurality of indicator lamps and said means comprises a plurality of flexible contacts arranged to be progressively short-circuited by said mechanism, to progressively energize said lamps by said mechanism.

11. In a sewing machine having a bed, a head, an arm extending therefrom and a standard connecting said arm and bed, upper and lower work feed means upon said head and bed, respectively, coupling mechanism between said feed means including control means, for continuously varying the feed stroke differential between said feed means during the operation of said machine, an indicator mounted upon said head having an indicating member visible in the normal viewing direction of the operator, and means connecting said mechanism with said indicator, to indicate the instantaneous feed stroke differential adjusted by said control means.

12. In a sewing machine having upper and lower arms, a 'bed, a head and a standard connecting one end of said arms, upper and lower work feed means upon said arms, coupling mechanism between said feed means including control means, for varying the feed stroke differential between said feed means continuously during the operation of said machine, indicating means mount-' ed upon said head and visible in the normal viewing direction of the operator, and means connecting said mechanism and said indicating means, to indicate the instantaneous feed stroke difierential adjusted by said control means.

References Cited in the file of this patent UNITED STATES PATENTS 1,081,453 Krug Dec. 16, 1913 1,243,160 Grieb Oct. 16, 1917 1,289,866 Moifatt et a1. Dec. 31, 1918 2,381,977 Mann Aug. 14, 1945 

